Researchers have discovered the first baby tyrannosaurus fossils in Alberta and Montana.
Experts believe the fossils are a rare discovery, as little is known about young tyrannosaurs and their evolution, according to a study published Monday in the Canadian Journal of Earth Sciences.
The study, led by Greg Funston, was based on two fossils: a small button claw found in Morrin, Alta, and a small mandible found in Montana.
Tyrannosaurs have been well researched, but fossils of tyrannosaur eggs or embryos have never been found – until now.
“What it does do is give us a starting point we did not have,” says Mark Powers, a PhD student at the University of Alberta and second author of the study.
“We split their growth rate and we don’t really have where they originated. To find monsters like this, which is definitely a tyrannosaurus in the shell or before it hatched, says something about the evolution.”
What do the discoveries mean?
The unprecedented findings provide a lot of information to researchers.
Using a 3D scan of the fossils and dimensions of the bones, researchers were able to find out more about the size of the hatch and prove that the samples were from unborn tyrannosaurs.
The 71.5-million-year-old claw found in Alberta has what Powers called a ‘cartilage cone’ at the back of the claw, meaning the area has not yet changed to bone and is still developing.
The approximately 75 million year old jaw found in Montana has triangular teeth with shallow roots, confirming that they were the first generation teeth of the tyrannosaurus.
“It fits in with many other discoveries and embryonic studies of birds and other dinosaurs found in the shell, so we suspect that it is an embryonic individual compared to an hatched one,” Powers said.
The location of these fossils is also telling.
The claw was found after a large sediment was taken from a digging expedition in Alberta a few years ago, Powers said.
In general, it is more difficult to obtain smaller remnants of dinosaurs.
Smaller fossils would have been more susceptible to the flowing rivers and floodplains of the Cretaceous, compared to larger dinosaur remains that are often buried deep and preserved in sediment, Powers said.
According to one professor, the areas where the fossils of the young dinosaurs were found are now possible sites for other important discoveries.
“We do not have much of a skeleton at all, these are relatively scrappy pieces. But because we know the area where tyrannosaurs seem to have made their nests, we know to go back to that place and comb with a fine tooth and find more and more things, ‘says Scott Persons, professor of paleontology at the College of Charleston in South Carolina.
“I think it’s definitely going to happen, so the big price of finding a tyrannosaur egg is going to happen.”
